| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1656786 | Surface and Coatings Technology | 2016 | 6 Pages |
•A novel nanocomposite Ni+CrAlYSiHfN/AlN duplex coating was fabricated on superalloy used in the aeroengine.•The growth of oxides layer on the coating system was studied by TEM.•The microstructure evolution mechanism of the coating at high temperature was studied.•The nanocomposite Ni+CrAlYSiHfN coating exhibited good oxidation resistance.
MCrAlY (M denotes Ni and/or Co) coatings are widely used on the turbine blades to protect the aeroengine at high temperature. However, the interdiffusion between coating/substrate and the coefficient of thermal expansion (CTE) mismatch between protective oxides layer/coating are the main factors that limit the service lifetime of MCrAlY coatings. In this work, a Ni+CrAlYSiHfN/AlN nanocomposite duplex coating system was designed to improve the weakness of conventional MCrAlY coatings. The nanocomposite coating system exhibited a low oxidation rate in the 1000 °C isothermal oxidation test and the oxidation rate constant of the coating system was 6.33 ∗ 10− 13 g2 cm− 4 s− 1 at the first 20 h, and then the TGO grew at a low constant of 1.49 ∗ 10− 13 g2 cm− 4 s− 1 until 200 h. Besides, the AlN diffusion barrier effectively inhibited the interdiffusion between coating/substrate. The evolution of coating microstructures and thermal growth oxides (TGO) at high temperature were studied with the aid of transmission electron microscopy.
